client9/ipcat — pull request #14 by ktheory (2013-02-27 21:19:37+00:00)
Title: Add Google IP ranges

This dataset of Google IP ranges comes from:

$ dig -t TXT _netblocks.google.com @ns1.google.com

This is useful for identifying requests from Google AppEngine, which I've noticed often uses the 74.125.*.* range.